Problem: $ D = \left[\begin{array}{rr}1 & 0 \\ 0 & 1 \\ 5 & 3\end{array}\right]$ What is $ D^{T}$ ?
Solution: To find the transpose, swap the rows and columns. $ D^{T}$ = $\left[\begin{array}{rrr}1 & 0 & 5 \\ 0 & 1 & 3\end{array}\right]$